Written by Angeline A. De Leon, Staff Writer. This study demonstrates the placebo effect of using sham acupuncture in combination with verbal suggestion to significantly reduce visually-induced nausea in participating women.
The employment of placebo interventions is based on the idea that the psychological expectation of symptom improvement, in the absence of any real physiological treatment, can be sufficient to improve clinical symptoms. This type of treatment, while unconventional, has shown some efficacy in treating various conditions, including nausea. A series of trials have demonstrated, for example, that patients undergoing placebo treatment are less susceptible to nausea than those in the untreated control condition (1). There is also evidence showing that gender may play a role in the efficacy of placebo interventions in the case of nausea treatment, with males, but not females, showing symptom reduction in response to verbal suggestions of improvement (2). To better understand the generalizability of such effects, a 2016 study by German researchers investigated how sham (dummy) acupuncture point stimulation, a procedure associated with large placebo effects (3), may influence visually-induced nausea in females.
A total of 20 healthy female participants (aged 18-50) with a history of motion sickness and susceptibility to visually-induced nausea participated in a randomized controlled pilot study using a within-subjects design. Participants were subjected to both a control condition (involving intake of natural health history) and a treatment condition (involving either active or placebo treatment) on two separate days, in randomized counterbalanced order across participants. Prior to treatment intervention, researchers induced a positive expectation towards placebo by telling participants that nausea would be treated either actively (involving electrical stimulation of an acupuncture point) or using a placebo procedure (involving sham acupuncture point stimulation). Participants were randomly allocated to either active or placebo treatment, but were not informed about which condition they were assigned. On both days, nausea was triggered using a moving visual stimulus which was presented for 20 minutes. Acupuncture point stimulation was delivered using a programmable transcutaneous electrical nerve stimulation (TENS) device, the active treatment group undergoing real TENS and the placebo group receiving a superficial massage. Following treatment, participants completed self-report measures assessing the intensities of expected and perceived nausea as well as symptoms of motion sickness.
Results of the study indicated that, in comparison to those in the control condition, participants receiving sham acupuncture stimulation experienced significantly less nausea, showing a large effect size of placebo treatment [F(1,18) = 43.52, p < 0.001; partial ŋ² = 0.71]. In accordance, the placebo group also showed reduced symptoms of motion sickness, in comparison to controls [F(1,18) = 8.23, p < 0.010; partial ŋ² = 0.31]. Researchers also found evidence suggesting the effective manipulation of expectancy in the experiment: participant expectation of nausea was significantly reduced following placebo treatment vs. no treatment, (p = 0.030).
Overall, findings of the pilot study provide evidence to support the efficacy of using sham acupuncture point stimulation in combination with verbal suggestion to produce a placebo effect on visually-induced nausea in women. Therefore, in addition to specific physiological treatments, the influence of verbal suggestions on participant expectation may facilitate the successful treatment of nausea. Future work is needed to replicate the reported effects, using larger sample sizes and more objective measures of nausea, including tests of cortical functioning.
Source: Müller, Veronika, Kirsten Remus, Verena Hoffmann, Matthias H. Tschöp, and Karin Meissner. “Effectiveness of a placebo intervention on visually induced nausea in women–A randomized controlled pilot study.” Journal of psychosomatic research 91 (2016): 9-11.
© 2016 Elsevier Inc. All rights reserved.
Posted May 2, 2017.
Angeline A. De Leon, M.A., graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program.
References:
- Hrobjarsson A, Gotzsche PC. Placebo interventions for all clinical conditions. Cochrane Database Systematic Review 1. 2010: CD003974.
- Horing B, Weimer K, Schrade D, et al. Reduction of motion sickness with an enhanced placebo instructions: an experimental study with healthy participants. Psychosomatic Medicine. 2013; 75(5): 497-504.
- Linde K, Niemann K, Schneider A, et al. How large are the nonspecific effects of acupuncture? A meta-analysis of randomized controlled trials. BMC Medicine. 2010; 8: 75.
